Image Processing Apparatus and Method

1. An image processing apparatus comprising: holding means for holding a plurality of conversion characteristics; calculation means for calculating an average luminance of an input image; obtaining means for obtaining a target luminance according to the average luminance by using one of the plurality of conversion characteristics, the one of the conversion characteristics being selected on the basis of the highlight and shadow points; setting means for setting an exposure compensation condition on the basis of the target luminance; and correction means for correcting the input image on the basis of the exposure compensation condition.

2. The apparatus according to claim 1 , wherein said calculation means selects a weak conversion characteristic when the highlight point is not less than a first threshold and the shadow point is not more than a second threshold, and selects a strong conversion characteristic in other cases.

3. The apparatus according to claim 2 , wherein the first threshold is larger than the second threshold.

4. An image processing apparatus comprising: first calculation means for calculating white balance of an input image on the basis of pixels having luminances less than a predetermined luminance in the highlight area of the input image; first setting means for setting a gradation correction condition on the basis of the white balance and the predetermined luminance; extraction means for extracting highlight and shadow points on the basis of a color distribution of an input image; second calculation means for calculating an average luminance of the input image and calculating a target luminance on the basis of the average luminance and the highlight and shadow points; and second setting means for setting an exposure compensation condition on the basis of the target luminance, wherein the apparatus corrects the input image on the basis of the gradation correction condition and the exposure compensation condition.

5. The apparatus according to claim 4 , further comprising correction means for correcting the input image on the basis of the exposure compensation condition set by said setting means.

6. The apparatus according to claim 4 , further comprising holding means for holding a conversion characteristic to be referred to when a target luminance is calculated by said calculation means.

7. An image processing method comprising the steps of: holding a plurality of conversion characteristics; calculating an average luminance of an input image; obtaining means for obtaining a target luminance according to the average luminance by using one of the plurality of conversion characteristics, the one of the conversion characteristics being selected on the basis of the highlight and shadow points; setting an exposure compensation condition on the basis of the target luminance; correcting the input image on the basis of the exposure compensation condition.

8. The method according to claim 7 , wherein said calculation step includes selecting a weak conversion characteristic when the highlight point is not less than a first threshold and the shadow point is not more than a second threshold, and selecting a strong conversion characteristic in other cases.

9. The method according to claim 8 , wherein the first threshold is larger than the second threshold.

10. A recording medium on which a program code for image correction processing is recorded, the program code comprising at least: code for holding a plurality of conversion characteristics; code for calculating an average luminance of an input image; code for obtaining means for obtaining a target luminance according to the average luminance by using one of the plurality of conversion characteristics, the one of the conversion characteristics being selected on the basis of the highlight and shadow points; code for setting an exposure compensation condition on the basis of the target luminance; and code for correcting the input image on the basis of the exposure compensation condition.

11. An image processing method comprising the steps of: calculating white balance of an input image on the basis of pixels having luminances less than a predetermined luminance in the highlight area of the input image; setting a gradation correction condition on the basis of the white balance and the predetermined luminance; extracting highlight and shadow points on the basis of a color distribution of an input image; calculating an average luminance of the input image and calculating a target luminance on the basis of the average luminance and the highlight and shadow points; and setting an exposure compensation condition on the basis of the target luminance, wherein the input image is corrected on the basis of the gradation correction condition and the exposure compensation condition.

12. A recording medium on which a program code for image correction processing is recorded, the program code comprising at least: code for calculating white balance of an input image on the basis of pixels having luminances less than a predetermined luminance in the highlight area of the input image; code for setting a gradation correction condition on the basis of the white balance and the predetermined luminance; code for extracting highlight and shadow points on the basis of a color distribution of an input image; code for calculating an average luminance of the input image and calculating a target luminance on the basis of the average luminance and the highlight and shadow points; and code for setting an exposure compensation condition on the basis of the target luminance, wherein the input image is corrected on the basis of the gradation correction condition and the exposure compensation condition.